Noncanonical Neural-Hemodynamic Coupling by Default and in Schizophrenia

Area of Science:

• Neuroscience
• Neuroimaging
• Psychiatric Research

Background:

• Current neuroimaging relies on canonical models of neurovascular coupling, assuming hemodynamic responses occur seconds after neural activity.
• Emerging evidence suggests noncanonical blood oxygen level dependent (BOLD) responses, which can be delayed under stress or aberrant in neuropsychiatric conditions.

Purpose of the Study:

• To investigate dynamic EEG-BOLD coupling and its temporal lags.
• To explore differences in neurovascular coupling between individuals with schizophrenia and healthy controls.

Main Methods:

• Simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) were recorded in 57 individuals with schizophrenia and 46 controls during rest.
• Alpha band power from EEG was correlated with voxelwise, time-lagged BOLD signals to assess dynamic EEG-BOLD coupling.

Main Results:

• Pronounced diversity in alpha-BOLD coupling temporal profiles was observed across the brain.
• Early coupling (0-2s lag) was noted in posterior default mode network (DMN), thalamus, and brainstem.
• Anterior DMN regions showed canonical lags (4-6s), with some participants exhibiting longer lags associated with stress and schizophrenia.

Conclusions:

• Hemodynamic signals are dynamically coupled to neural activity across distributed networks.
• The hemo-neural lag may be associated with subjective arousal or stress.
• Further research into neurovascular coupling in psychiatric conditions is warranted.